3D Scanner Robot Calibration for Low-Cost Position Accuracy
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Solution Overview
Problem
Industrial 6-axis robots face low position accuracy, which hinders precise movement in three-dimensional space, and existing calibration methods using laser trackers are expensive and impractical for real-world applications.
Innovation Solution
A method and apparatus utilizing a 3D scanner mounted on the robot to scan objects in multiple positions, with a scan position controller, data receiver, and parameter calibrator to calculate calibration values for improving robot position accuracy, enabling economical robot mastering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser tracker is used for robot calibration, then position accuracy is improved, but cost increases prohibitively
Solution Approach 1:
The patent replaces the expensive laser tracker with a 3D scanner that is more economical and practical for real-world job sites. The 3D scanner captures multiple images of calibration objects at different robot positions, and through computational processing, derives calibration parameters without requiring costly specialized equipment.
Solution Approach 2:
The patent substitutes the mechanical laser tracker system with a vision-based 3D scanning system. Instead of using laser ranging measurements, the system uses multiple 2D images captured by the 3D scanner from different angles and positions to reconstruct 3D information and calculate calibration parameters, replacing mechanical measurement with optical imaging and computational geometry.
2Ease of manufacture
If 3D scanner is used for robot calibration, then cost is reduced, but measurement precision may be compromised
Solution Approach 1:
The patent divides the calibration process into multiple discrete robot positions, with calibration objects placed at different locations around the robot. The 3D scanner captures images at each position, and the system processes each position's data separately to derive calibration parameters. This segmentation allows the use of multiple inexpensive measurements to achieve high precision through statistical aggregation and error compensation.
Solution Approach 2:
The patent transitions from 2D image data to 3D spatial information by capturing multiple images from different angles and robot positions. The system reconstructs three-dimensional coordinates of calibration object features from two-dimensional scanner images, and uses these 3D points to calculate robot calibration parameters. This dimensional transformation enables precise measurement using the 3D scanner.
3Measurement precision
If robot moves to multiple scan positions, then calibration accuracy is improved, but time consumption increases
Solution Approach 1:
The patent pre-arranges multiple calibration objects at specific positions around the robot before calibration begins. The scan position controller is pre-programmed with the optimal positions and trajectories for scanning each calibration object. This preliminary setup allows the robot to efficiently move through predetermined positions without real-time decision-making, reducing overall calibration time while maintaining accuracy.
Solution Approach 2:
The patent implements continuous scanning and data acquisition as the robot moves through multiple positions. Instead of stopping at each position to capture images, the system continuously captures data during robot movement, and processes the continuous stream of images to derive calibration parameters. This continuous action reduces idle time and speeds up the calibration process while maintaining measurement precision.
Data Source
AI summary
A robot position calibration apparatus is disclosed including a scan position controller configured to control the position of the robot by individually setting parameter sets related to the position of the robot for causing a scanner mounted on an end of the robot to scan an object in multiple scan positions around the robot, and a data receiver configured to receive, from the scanner, multiple scan data items generated by the scanner scanning the object in each of the multiple scan positions, and a parameter calibrator configured to calculate calibration values for the parameter sets having been individually set, by using multiple position information items corresponding to the parameter sets and the multiple scan data items.